String to Date Example

•         Java String to Date Example.
          This Java String to Date example shows how to convert Java String to Date object.
   */
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  
  
  public class JavaStringToDate {
          public static void main(String args[]){
  
  
                  //Java String having date
                  String strDate = “21/08/2011”;
  
  
                  /*
                   * To convert Java String to Date, use
                   * parse(String) method of SimpleDateFormat class.
                   *
                   * parse method returns the Java Date object.
                   */
  
  
                  try{
  
  
                          /*
                           * Create new object of SimpleDateFormat class using
                           * SimpleDateFormat(String pattern) constructor.
                           */
  
  
                          SimpleDateFormat sdf = new SimpleDateFormat(“dd/MM/yyyy”);
  
  
                          //convert Java String to Date using parse method of SimpleDateFormat
                          Date date = sdf.parse(strDate);
  
  
                          //Please note that parse method throws ParseException if the String date could not be parsed.
  
  
                          System.out.println(“Date is: “ + date);
  
  
                  }catch(ParseException e){
                          System.out.println(“Java String could not be converted to Date: “ + e);
                  }
          }
  }
  
  
  /*
  Output of Java String to Date example would be
  Fri Jan 21 00:00:00 IST 2011
  */

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String to Lower Case example

1. /*
           Java String to Lower Case example.
           This Java String to Lower Case example shows how to change the string to lower case
           using toLowerCase method of String class.
   */
   public class StringToLowerCaseExample {
   
   
           public static void main(String[] args) {
   
   
                   String str = “STRING TOLOWERCASE EXAMPLE”;
   
   
                   /*
                    * To change the case of string to lower case use,
                    * public String toLowerCase() method of String class.
                    *
                    */
   
   
                    String strLower = str.toLowerCase();
   
   
                    System.out.println(“Original String: “ + str);
                    System.out.println(“String changed to lower case: “ + strLower);
           }
   }
   
   
   /*
   Output would be
   Original String: STRING TOLOWERCASE EXAMPLE
   String changed to lower case: string tolowercase example
   */

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String to UpperCase example

1. /*
           Java String to Upper Case example.
           This Java String to Upper Case example shows how to change the string to upper case
           using toUpperCase method of String class.
   */
   
   
   public class StringToUpperCaseExample  
   {
   
   
           public static void main(String[] args)  
   {
   
   
                   String str = “string touppercase example”;
   
   
                   /*
                    * To change the case of string to upper case use,
                    * public String toUpperCase() method of String class.
                    *
                    */
   
   
                    String strUpper = str.toUpperCase();
   
   
                    System.out.println(“Original String: “ + str);
                    System.out.println(“String changed to upper case: “ + strUpper);
           }
   }
   
   
   /*
   Output would be
   Original String: string touppercase example
   String changed to upper case: STRING TOUPPERCASE EXAMPLE*/

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String Trim Example

1. /*
           Java String Trim Example.
           This Java String trim example shows how to remove leading and trailing space
           from string using trim method of Java String class.
   */
   
   
   public class RemoveLeadingTrailingSpace  
   {
   
   
           public static void main(String[] args)  
   {
   
   
                   String str = ”   String Trim Example   “;
   
   
                   /*
                    * To remove leading and trailing space from string use,
                    * public String trim() method of Java String class.
                    */
   
   
                    String strTrimmed = str.trim();
   
   
                    System.out.println(“Original String is: “ + str);
                    System.out.println(“Removed Leading and trailing space”);
                    System.out.println(“New String is: “ + strTrimmed);
           }
   }
   
   
   /*
   Output would be
   Original String is:    String Trim Example  
   Removed Leading and trailing space
   New String is: String Trim Example
   */

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String Split Example

*

• Java String split example.
  This Java String split example describes how Java String is split into multiple
  Java String objects.
  */
  
  
  public class JavaStringSplitExample{
  
  
    public static void main(String args[]){
    /*
    Java String class defines following methods to split Java String object.
    String[] split( String regularExpression )
    Splits the string according to given regular expression.
    String[] split( String reularExpression, int limit )
    Splits the string according to given regular expression. The number of resultant
    substrings by splitting the string is controlled by limit argument.
    */
    /* String to split. */
    String str = “one-two-three”;
    String[] temp;
  
  
    /* delimiter */
    String delimiter = “-“;
    /* given string will be split by the argument delimiter provided. */
    temp = str.split(delimiter);
    /* print substrings */
    for(int i =0; i < temp.length ; i++)
      System.out.println(temp[i]);
  
  
    /*
    IMPORTANT : Some special characters need to be escaped while providing them as
    delimiters like “.” and “|”.
    */
  
  
    System.out.println(“”);
    str = “one.two.three”;
    delimiter = “\\.”;
    temp = str.split(delimiter);
    for(int i =0; i < temp.length ; i++)
      System.out.println(temp[i]);
  
  
    /*
    Using second argument in the String.split() method, we can control the maximum
    number of substrings generated by splitting a string.
    */
    System.out.println(“”);
    temp = str.split(delimiter,2);
    for(int i =0; i < temp.length ; i++)
      System.out.println(temp[i]);
  
  
    }
  
  
  }
  
  
  /*
  OUTPUT of the above given Java String split Example would be :
  one
  two
  three
  one
  two
  three
  one
  two.three
  */

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String Replace Example

1. /*
   Java String replace example.
   This Java String Replace example describes how replace method of java String class
   can be used to replace character or substring can be replaced by new one.
   */
   public class JavaStringReplaceExample{
   
   
     public static void main(String args[]){
   
   
       /*
       Java String class defines three methods to replace character or substring from
       the given Java String object.
       1) String replace(int oldChar, int newChar)
       This method replaces a specified character with new character and returns a
       new string object.
       2) String replaceFirst(String regularExpression, String newString)
       Replaces the first substring of this string that matches the given regular
       expression with the given new string.
       3) String replaceAll(String regex, String replacement)
       Replaces the each substring of this string that matches the
       given regular expression with the given new string.
       */
   
   
       String str=“Replace Region”;
   
   
       /*
       Replaces all occourances of given character with new one and returns new
       String object.
       */
       System.out.println( str.replace( ‘R’,‘A’ ) );
   
   
       /*
       Replaces only first occourances of given String with new one and
       returns new String object.
       */
       System.out.println( str.replaceFirst(“Re”, “Ra”) );
   
   
       /*
       Replaces all occourances of given String with new one and returns
       new String object.
       */
       System.out.println( str.replaceAll(“Re”, “Ra”) );
   
   
     }
   
   
   }
   
   
   /*
   OUTPUT of the above given Java String Replace Example would be :
   Aeplace Aegion
   Raplace Region
   Raplace Ragion
   */

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String Length Example

1. /*
     Java String Length Example
     This example shows how to get a length of a given String object.
   */
   
   
   public class StringLengthExample 
   {
   
   
     public static void main(String[] args)  
   {
       //declare the String object
       String str = “Hello World”;
   
   
       //length() method of String returns the length of a String.
       int length = str.length();
       System.out.println(“Length of a String is : “ + length);
     }
   }
   
   
   /*
   Output of a program would be:
   Length of a String is : 11
   */

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String Contains example

•        This Java String contains examples shows how to use contains method of Java String class.
   */
  public class JavaStringContains {
          public static void main(String args[]){
                  String str1 = “Hello World”;
                  String str2 = “Hello”;
  
  
                  /*
                   * To check whether the string contains specified character sequence use,
                   * boolean contains(CharSequence sq)
                   * method of Java String class.
                   *
                   * This method returns true if the string contains given character sequence.
                   * Please note that contains method is added in Java 1.5  
                   */
                 
                  boolean blnFound = str1.contains(str2);
                  System.out.println(“String contains another string? : “ + blnFound);
  
  
                  /*
                   * Please also note that the comparison is case sensitive.
                   */
                 
          }
  }
  
  
  /*
  Output of Java String contains example would be
  String contains another string? : true
  */

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String Concat Example

1. /*
           Java String Concat Example.
           This Java String concat example shows how to concat String in Java.
    */
   public class JavaStringConcat {
           public static void main(String args[]){
                   /*
                    * String concatenation can be done in several ways in Java.
                    */
   
   
                   String str1 = “Hello”;
                   String str2 = ” World”;
   
   
                   //1. Using + operator
                   String str3 = str1 + str2;
                   System.out.println(“String concat using + operator : “ + str3);
   
   
                   /*
                    * Internally str1 + str 2 statement would be executed as,
                    * new StringBuffer().append(str1).append(str2)
                    *
                    * String concatenation using + operator is not recommended for large number
                    * of concatenation as the performance is not good.
                    */
                  
                   //2. Using String.concat() method
                   String str4 = str1.concat(str2);
                   System.out.println(“String concat using String concat method : “ + str4);
   
   
                   //3. Using StringBuffer.append method
                   String str5 = new StringBuffer().append(str1).append(str2).toString();
                   System.out.println(“String concat using StringBuffer append method : “ + str5);
           }
   
   
   }
   
   
   /*
   Output of Java String concat example would be
   String concat using + operator : Hello World
   String concat using String concat method : Hello World
   String concat using StringBuffer append method : Hello World
   */

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String Compare Example

1. /*
   Java String compare example.
   This Java String compare example describes how Java String is compared with another
   Java String object or Java Object.
   */
   
   
   public class JavaStringCompareExample{
   
   
     public static void main(String args[]){
   
   
     /*
     Java String class defines following methods to compare Java String object.
     1) int compareTo( String anotherString )
     compare two string based upon the unicode value of each character in the String.
     Returns negative int if first string is less than another
     Returns positive int if first string is grater than another
     Returns 0 if both strings are same.
     2) int compareTo( Object obj )
     Behaves exactly like compareTo ( String anotherString) if the argument object
     is of type String, otherwise throws ClassCastException.
     3) int compareToIgnoreCase( String anotherString )
     Compares two strings ignoring the character case of the given String.
     */
   
   
     String str = “Hello World”;
     String anotherString = “hello world”;
     Object objStr = str;
   
   
     /* compare two strings, case sensitive */
     System.out.println( str.compareTo(anotherString) );
     /* compare two strings, ignores character case  */
     System.out.println( str.compareToIgnoreCase(anotherString) );
     /* compare string with object */
     System.out.println( str.compareTo(objStr) );
   
   
     }
   
   
   }
   
   
   /*
   OUTPUT of the above given Java String compare Example would be :
   -32
   0
   0
   */

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String Array Length Example

1. /*
           Java String Array Length Example
           This Java String Array Length example shows how to find number of elements
           contained in an Array.
    */
   
   
   public class JavaStringArrayLengthExample {
   
   
           public static void main(String args[]){
   
   
                   //create String array
                   String[] strArray = new String[]{“Java”, “String”, “Array”, “Length”};
   
   
                   /*
                    * To get length of array, use length property of array.
                    */
                   int length = strArray.length;
   
   
                   System.out.println(“String array length is: “ + length);
   
   
                   //print elements of an array
                   for(int i=0; i < length; i++){
                           System.out.println(strArray[i]);
                   }
           }
   }
   
   
   /*
   Output of above given Java String length example would be
   String array length is: 4
   Java
   String
   Array
   Length
   */

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String Array Contains Example

1. /*
           Java String Array Contains Example
           This Java String Array Contains example shows how to find a String in
           String array in Java.
    */
   
   
   import java.util.Arrays;
   
   
   public class StringArrayContainsExample {
   
   
           public static void main(String args[]){
   
   
                   //String array
                   String[] strMonths = new String[]{“January”, “February”, “March”, “April”, “May”};
   
   
                   //Strings to find
                   String strFind1 = “March”;
                   String strFind2 = “December”;
   
   
                   /*
                    * There are several ways we can check whether a String array
                    * contains a particular string.
                    *
                    * First of them is iterating the array elements and check as given below.
                    */
                  
                   boolean contains = false;
   
   
                   //iterate the String array
                   for(int i=0; i < strMonths.length; i++){
   
   
                           //check if string array contains the string
                           if(strMonths[i].equals(strFind1)){
   
   
                                   //string found
                                   contains = true;
                                   break;
   
   
                           }
                   }
   
   
                   if(contains){
                           System.out.println(“String array contains String “ + strFind1);
                   }else{
                           System.out.println(“String array does not contain String “ + strFind1);
                   }
   
   
                   /*
                    * Second way to check whether String array contains a string is to use
                    * Arrays class as given below.
                    */
   
   
                   contains = Arrays.asList(strMonths).contains(strFind1);
                   System.out.println(“Does String array contain “ + strFind1 + “? “ + contains);
   
   
                   contains = Arrays.asList(strMonths).contains(strFind2);
                   System.out.println(“Does String array contain “ + strFind2 + “? “ + contains);
   
   
           }
   }
   
   
   /*
   Output of above given Java String Array Contains example would be
   String array contains String March
   Does String array contain March? true
   Does String array contain December? false
   */

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Stack trace to String Example

1. /*
           Java Stacktrace to String Example
           This Java Stacktrace to String example shows how to get Stacktrace of any exception
           to String.
    */
   import java.io.PrintWriter;
   import java.io.StringWriter;
   
   
   public class StackTraceToStringExample {
   
   
           public static void main(String args[]){
   
   
                   try{
   
   
                           //this will throw NumberFormatException
                           Integer.parseInt(“Not a number”);
   
   
                   }catch(NumberFormatException e){
   
   
                           /*
                            * To convert Stacktrace to String in Java, use
                            * printStackTrace(PrintWrite pw) method of Throwable
                            * class.
                            */
                          
                           //create new StringWriter object
                           StringWriter sWriter = new StringWriter();
   
   
                           //create PrintWriter for StringWriter
                           PrintWriter pWriter = new PrintWriter(sWriter);
   
   
                           //now print the stacktrace to PrintWriter we just created
                           e.printStackTrace(pWriter);
   
   
                           //use toString method to get stacktrace to String from StringWriter object
                           String strStackTrace = sWriter.toString();
   
   
                           System.out.println(“Stacktrace converted to String: “ + strStackTrace);
                   }
           }
   
   
   }
   
   
   /*
   Output of above given Java Stacktrace to String would be
   Stacktrace converted to String: java.lang.NumberFormatException: For input string: “Not a number”
           at java.lang.NumberFormatException.forInputString(Unknown Source)
           at java.lang.Integer.parseInt(Unknown Source)
           at java.lang.Integer.parseInt(Unknown Source)
           at StackTraceToStringExample.main(StackTraceToStringExample.java:16)
   */

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Sort String Array Example

1. /*
           Java Sort String Array Example
           This Java Sort String Array example shows how to sort an array of Strings
           in Java using Arrays.sort method.
    */
   import java.util.Arrays;
   
   
   public class SortStringArrayExample 
   {
   
   
           public static void main(String args[]) 
   {
   
   
                   //String array
                   String[] strNames = new String[]{“John”, “alex”, “Chris”, “williams”, “Mark”, “Bob”};
   
   
                   /*
                    * To sort String array in java, use Arrays.sort method.
                    * Sort method is a static method.               *
                    */
   
   
                   //sort String array using sort method
                   Arrays.sort(strNames);
   
   
                   System.out.println(“String array sorted (case sensitive)”);
   
   
                   //print sorted elements
                   for(int i=0; i < strNames.length; i++)
    {
                           System.out.println(strNames[i]);
                   }
   
   
                   /*
                    * Please note that, by default Arrays.sort method sorts the Strings
                    * in case sensitive manner.
                    *
                    * To sort an array of Strings irrespective of case, use
                    * Arrays.sort(String[] strArray, String.CASE_INSENSITIVE_ORDER) method instead.
                    */
   
   
                   //case insensitive sort
                   Arrays.sort(strNames);
   
   
                   System.out.println(“String array sorted (case insensitive)”);
                   //print sorted elements again
                   for(int i=0; i < strNames.length; i++) 
   {
                           System.out.println(strNames[i]);
                   }
   
   
           }
   }
   
   
   /*
   Output of above given Java Sort String Array example would be
   String array sorted (case sensitive)
   Bob
   Chris
   John
   Mark
   alex
   williams
   String array sorted (case insensitive)
   Bob
   Chris
   John
   Mark
   alex
   williams
   */

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